Superalloys have been used in the metal industry for many years. A superalloy or a high-performance alloy is a metal alloy that exhibits excellent mechanical strength and creep resistance, e.g., at high temperatures, high surface stability, and high resistance to corrosion and oxidation. Superalloys typically have an austenitic, face-centered, cubic crystal structure. Alloying elements of superalloys usually include nickel, cobalt, or nickel-iron. Superalloy development relies on chemical and process innovations, and is driven primarily by the aerospace industry and by power industries such as the industrial gas-turbine and marine-turbine industries.
Examples of superalloys are Hasteloy, Waspaloy, Rene alloys (e.g., Rene 41, Rene 80, Rene 95), Haynes alloys, Incoloy, single crystal alloys, and Inconel, which includes a family of austenitic, nickel-based superalloys, typically used in high temperature applications.
Inconel, as with some other superalloys, includes oxidation and corrosion resistant materials that perform well under extreme conditions. For example, when heated Inconel forms a thick, stable, passivating oxide layer that protects its surface from a plurality of undesired effects. Therefore, Inconel retains its strength over a wide range of temperatures and is attractive for use in high temperature applications, whereas other materials such as aluminum or steel perform unsatisfactorily in such applications.
Nevertheless, Inconel and other superalloys are highly difficult to shape and machine, e.g., due to their rapid work-hardening during the machining process. For example, after completion of a first machine pass on a work-piece of Inconel, the rapid work-hardening causes, in subsequent machine passes, undesired plastic and elastic deformations of various areas of the work-piece that come into interaction with the cutting tool.
A present solution for overcoming the above-mentioned disadvantages includes supplying coolant fluid provided by an external adaptor, with a pressure of approximately 70-80 bars, on the general cutting area. The applied coolant fluid contributes to expel heat generated in the machining process. However, the present solution including providing of coolant fluid, for example, using known cemented carbide cutting inserts, limits the cutting speed (Vc) of the work-piece to approximately 40-60 meters per minute, which is a relatively limited cutting speed, compared to cutting speeds of other cutting operations. For example, the low cutting speed leads to high machining costs and thus to high manufacturing costs.
It is the object of the present invention to provide a machining method, and a cutting insert to perform the machining method, which significantly reduce or overcome the aforementioned disadvantages.